65 lines
1.6 KiB
Plaintext
65 lines
1.6 KiB
Plaintext
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//---------------------------------------------------------------------------//
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// Copyright (c) 2013-2014 Kyle Lutz <kyle.r.lutz@gmail.com>
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//
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// Distributed under the Boost Software License, Version 1.0
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// See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt
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//
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// See http://boostorg.github.com/compute for more information.
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//---------------------------------------------------------------------------//
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#ifndef BOOST_COMPUTE_FUNCTIONAL_IDENTITY_HPP
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#define BOOST_COMPUTE_FUNCTIONAL_IDENTITY_HPP
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namespace boost {
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namespace compute {
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namespace detail {
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template<class T, class Arg>
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struct invoked_identity
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{
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typedef T result_type;
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invoked_identity(const Arg &arg)
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: m_arg(arg)
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{
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}
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Arg m_arg;
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};
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} // end detail namespace
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/// Identity function which simply returns its input.
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///
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/// For example, to directly copy values using the transform() algorithm:
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/// \code
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/// transform(input.begin(), input.end(), output.begin(), identity<int>(), queue);
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/// \endcode
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///
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/// \see \ref as "as<T>", \ref convert "convert<T>"
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template<class T>
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class identity
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{
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public:
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/// Identity function result type.
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typedef T result_type;
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/// Creates a new identity function.
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identity()
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{
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}
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/// \internal_
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template<class Arg>
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detail::invoked_identity<T, Arg> operator()(const Arg &arg) const
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{
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return detail::invoked_identity<T, Arg>(arg);
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}
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};
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} // end compute namespace
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} // end boost namespace
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#endif // BOOST_COMPUTE_FUNCTIONAL_IDENTITY_HPP
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